The present invention relates to the production of borosilicate glass, in particular a borosilicate glass substrate with a surface suitable for modification, and the glass obtained according to the method according to the invention, and the use thereof.
The use of glass as a carrier substrate for a large number of uses is known per se. According to the usual procedure, a desired chemical substrate (modifying agent), such as biomolecules, is immobilized on the glass surface. This is usually carried out using SiOH groups, which are freely available on the glass surface. To obtain a sufficient number or density of modifying agents, the number of reactive SiOH groups must be increased. This can be accomplished, e.g., using treatment in a gas plasma. A further method for increasing the surface reactivity of glass is to treat it with alkali hydroxides, in particular sodium hydroxide. Glass surfaces that have been treated in this manner then react easily with other reagents, and a coated glass surface is obtained. In this manner, it is possible to covalently bond the surfaces of glass with a large number of compounds to obtain certain properties, such as dirt-proof properties, by bonding with silanes, or it is possible to obtain certain reactions, e.g., with biomolecules.
The term “biochip” refers to devices that have a biological or organic material that is immobilized on the solid carrier substrate. Silicon wafers, thin glass plates, plastic or nylon membranes serve as a common carrier substrate for chips of this type. Aluminum has also been used as carrier material. Glass is typically preferred, however, due to its surface properties, low natural fluorescence compared to other plastic materials, and its resistance to chemical substances and temperature stability. It is also resistant to aging. It has been demonstrated, however, that glass also has disadvantages, e.g., a natural fluorescence. The treatment methods described hereinabove are either complex, however, such as plasma treatment, or they result in an unsatisfactorily activated surface.